In a picturesque village of bamboo huts near China's border with Burma, 37-year-old Sha Wang complains he has been sick for over a year.

"I always feel tired, and I can't work in the fields. I haven't been to the doctor as I don't have any money," he said.

Other villagers know what is wrong, they say Sha Wang has Aids.

He admits sharing needles to inject heroin for years. Now he has exiled himself to a hut to protect the health of his two sons.

"I'm scared of infecting my little devils. If you spend time with other people, you just can't say how the disease is passed on. I've heard you can infect people through eating with them," he said.

His ignorance is shocking, especially since he says at least 20 people in his village, Laxiang, have suffered the same disease, another 20 in the next settlement.

They are victims of geography, living on the edge of the Golden Triangle, where heroin crosses the border from Burma, often bringing with it the modern scourge of Aids. The area has one of the highest infection rates in China.

Thirty kilometres from where Sha Wang lies in his shack is a sleepy town, Ruili.

This is ground zero for China's Aids epidemic.

In 1989, local officials found almost 150 heroin users were HIV positive - the first confirmed cases in China.

And since then Aids has devastated poor farming communities in the area.

Li Chaoliang works for the Yunnan Provincial Working Committee for HIV/Aids control, and he says the situation is critical.

"The impact is obvious in border areas where Aids is prevalent. In some districts the population is beginning to fall. It's actually shrinking. And the influence of Aids on economic growth is very serious. Aids is influencing the whole of social development in these areas," he said.

Strips of pink-lit karaoke bars line the streets of Ruili, and young girls sprawl on sofas singing pop songs as they wait for passing custom. The sex industry is poorly disguised. But these girls could also be unsuspecting incubators for Aids.

Aids is increasingly being spread by sex in Yunnan

Mrs Yang runs a brothel where 12 girls work. She tells me condom use is the norm, but it does not always happen.

"Most customers use condoms, but sometimes the girls come back and they say to me this client is difficult to deal with. That sometimes happens. But it's quite rare," she said.

Officials say the spread of Aids through sex is on the rise in Yunnan province, a sign that the disease is working its way into the population at large.

Beijing responds

In the past year, the central government in Beijing has tried to bring the problem of Aids into the open across China. But has it succeeded?

Wu Zunyou from the National Centre for HIV/Aids intervention says the changes have been marked.

"It's a great change in terms of finding the number of HIV infected people. And also for effective but sensitive interventions such as condom promotion and methadone for heroin addicts and also for needle exchange programmes. The central government allocated far more money for these programmes," he said.

China's budget for combating Aids doubled to $98m in 2004.

In Yunnan's provincial capital, Kunming, that increase is symbolised by a new needle exchange project.

The centre also includes games rooms and a library about HIV/Aids. It only opened in March, but more than 1,000 heroin addicts now use its services.

Kunming's needle exchange programme is supporting addicts

Project manager Feng Yu said its existence showed how the government's attitude had changed in the last year.

"The police and local government have been quite supportive of our project. I think our government has begun to realise that Aids has serious consequences for the whole society and the country."

One heroin addict, 35-year-old Mr Wang, comes to the centre every few days for new needles.

"Before I didn't really know much about Aids," he said. "I've learned more by coming here."

So it seems the message is starting to trickle down in urban centres.

But it is not getting through to those that need it most. Like one young addict near the Burmese border, who admitted he still shared needles with others.

"We just use each other's needles freely," he said. "And sometimes, when people throw away needles, I'll pick them up and use them again.

"We don't know if it's dangerous, we're not scared to use them. We need money to buy new needles and we don't have any money. "

His world has contracted to one pressing need - to get the next fix, whatever the cost.

And that cost is being passed on to other drug users blinded by need, to their unsuspecting families and, ultimately, to the government in lost lives.

The Chinese leadership has turned its attention to the Aids crisis. But it has done so too late for this young addict, and for Sha Wang, whose ignorance is proof of the government's past failure.